RT Book, Section A1 Srour, Samer A. A1 Champlin, Richard E. A1 Ciurea, Stefan O. A2 Kantarjian, Hagop M. A2 Wolff, Robert A. A2 Rieber, Alyssa G. SR Print(0) ID 1190834065 T1 Alternative Donor Transplants: Haploidentical Hematopoietic Stem Cell Transplantation T2 The MD Anderson Manual of Medical Oncology, 4e YR 2022 FD 2022 PB McGraw Hill Education PP New York, NY SN 9781260467642 LK hemonc.mhmedical.com/content.aspx?aid=1190834065 RD 2024/11/05 AB KEY CONCEPTSAllogeneic stem cell transplantation (allo-SCT) remains the only curative intervention for a variety of high-risk hematologic malignancies. Haploidentical grafts from a first-degree related mismatched donor extends the applicability of this lifesaving treatment to a large proportion of patients who otherwise do not have a suitable human leukocyte antigen–matched donor.Breakthrough advances achieved over past decade in controlling the bidirectional alloreactivity and in graft engineering have led to a decreased incidence of complications, including graft-versus-host disease and nonrelapse mortality (NRM), without compromising the graft-versus-tumor effect.The use of haploidentical transplantation continues to increase with growing evidence for its effectiveness in several myeloid and lymphoid neoplasms. Haploidentical use has taken precedence compared with some other alternative donor sources given its immediate availability and cost-effectiveness.Fully matched related donors remain the preferred graft source for allo-SCT. However, several transplant registry studies in United States and Europe have confirmed comparable survival outcomes between matched unrelated and haploidentical transplants.The results of the large phase 3 randomized Bone and Marrow Transplant Clinical Trials Network multicenter clinical trials were reported recently confirming superiority of haploidentical transplant over double cord transplant in terms of improved overall survival and decreased NRM.Several factors are considered when choosing the best haploidentical donor. The donor-specific antibodies remain one of the most important factors to consider because the presence of antibodies is associated with a high risk of graft failure. Younger donors, male donors, fathers rather than mothers, and first-degree to second-degree donors are preferred graft sources for recipients of haploidentical transplants.